Resinous compositions of matter and methods for preparing same

ABSTRACT

Polyepoxides are cured by reacting them with 1,2,3,4-cyclopentanetetracarboxylic dianhydride.  The preferred polyepoxides are:-bis-cyclopentenyl ether diepoxides, dicyclopentadiene diepoxides, 3,4-epoxy-6-methylcyclohexylmethyl-3,4-epoxy-6-methyl cyclo hexane-carboxylate, and bis-phenol A/epichlorhydrin reaction products.ALSO:It is stated that 1,2,3,4-cyclopentane tetra carboxylic di-anhydride was prepared by the nitric acid oxidation of the anhydride of 4,5-dicarboxylic bicycloheptene (carbic anhydride). The dianhydride is used to cure polyepoxides (see Group IV(a)).

United States Patent r 3,102,872 RESINOUS COMPOSITIONS OF MATTER AND METHODS FOR PREPARING SAME Arthur W. Carlson and George C. Schwciker, Chicago,

Ill., assignors to Velsicol Chemical Corporation, Chicago, Ill., a corporation of Illinois No Drawing. Filed June 24, 1959, Ser. No. 822,448

17 Claims. (Cl. 260-47) This invention relates to new epoxy resin compositions. In particular, this invention relates to. cured epoxy resin compositions produced by reacting 1,2,3,4-cyclopentanetetracarboxylic dianbydride and a polyepoxide compound.

The use of epoxy resins has increased substantially in the past few years and has spread to a wide variety of applications, including castings, epoxy/ glass laminates and protective coatings. In order to be of ultimate value for these applications the epoxy resin must be thermoset or cross-linked. This type of material is preparable by the curing of materials containing a plurality of epoxy groups, hereinafter referred to as polyepoxide compounds or po-lyepoxides.

A wide variety of polyepoxide compounds has been and can be utilized for this purpose, the preponderance thereof being =diepoxides. Perhaps the most commercially available materials in this classification are the reaction products of an epihalogenhydrin, usually epichlorohydrin, and a bisphenol, particularly 2,2abis(4,4-hydroxyphenyl)- propane. These materials are sold under various trade names such asEpon and Ara-ldite. Depending on the proportions and exact identities of the reactants, this reaction product can be a solid or liquid, having an epoxide equivalent (gram of material per oxirane oxygen group) of varying magnitude. In addition, other compounds containing a plurality of oxirane oxygen .groups are within this classification, with diepoxides being a preferred group. In order to be of commercial value it is necessary tor the curing reaction to proceed at a satisfactory rate, to prepare a product of reasonable pot life and for the product to have good physical, chemical and/or electrical properties. Of course, the ultimate use of the product dictates which of the properties are of importance and the degree of any specific property required for the epoxy resin composition.

Often it has been found that the commercially available cured epoxy resin compositions lack one or more of the desired properties, usually heat stability, impact resistance, high heat distortion temperature, and chemical resistivity. Further, these materials may lack a specific combination of desirable properties, although they may possess certain properties in satisfactory proportions. In

addition, the reactivity of many known curing agents is either too low, so as to prolong the curing time, or toohigh, unreasonably shortening the pot life of the material.

It is therefore an object of the present invention to produce epoxy resin compositions having superior properties, particularly in regard to heat stability, impact resistance, and a high heat distortion temperature. I

Still another object of the present invention is. to provide a method for the curing of epoxy compounds utilizing curing agents of optimum reactivity.

Other objects of the present invention will become apparent from the ensuing description.

Unexpectedly, it has been found, in accordance with the present invention, that epoxy resin compositions produced by the utilization of 1,2,3,4-cyclopentanetetracarboxylic dianhydride as the curing agent exhibit superior physical, chemical and electrical characteristics. Despite the multifunctionality 02E this compound, its reactivity is sufficiently slow to sustain the polyepoxy composition reaction mixtures pot life at a reasonable {level tor, comice Patented Sept. 3, 1963 mercial purposes. In general, dianhydrides are highly reactive materials, often necessitating their use in a diluted manner. One method of dilution is the use of the dianhydride in combination with less reactive compounds, such as ordinary monoanhydrides. This use of other less reactive materials in combination with a rdianhydride has the unfortunate consequence of destroying or severely minimizing the desirable properties attributed to the epoxy resin composition by the dianhydride. The reactivity of 1,2,3,4-cyclopentanetetracarboxylic dianhydride permits its application by itself as a curing agent for polyepoxy compounds, imparting thereto superior chem ical, electrical and physical properties, particularly heat stability, impact resistance, and high heat distortion temperature.

The preparation of 1,2,3,4-cyclopentanetetracarboxylic dianhydride is reported in the literature, cf., Alder and Schneider, Ann. 524, 189-202 (1936), wherein it is prepared by the two step process of first reacting car-bio acid and potassium permanganate and then reacting the product thereof with acetyl chloride. While the l,2,3,4- cyclopentanetetracarboxylic dianhydride used in sheensuing examples was prepared .by the nitric acid oxidation of carbic anhydride (4,5-dicarboxylicbicycloheptene), the mode of preparation is not critical to the present inven, tion.

In the curing of the lepoxide compounds in accordance with the present invention it is theoretically necessary to react 0.25 mol of 1,2,3,4-cyclopentanetetracarboxyilic dianhydride per epoxide equivalent of the polyepoxide composition. cyclopentanetetracarboxylic dianhydride per epoxide equivalent of the polyepoxide compound is operable and fromyabout 0.2 to 0.3 mol of 1,2,3,4rcyclopentanetetracarboxylic dianhydride is a preferred operation of the present invention. i

In orderto properly cure the polyepoxide composition with 1,2,3,4-tetracarboxycyclopentane, dianhydride it is necessary to heat thereaction mixture to an elevated temperature, preferably between about C. and 200 C. for a suflicient time period as determined in part by the identity of the polyepoxideicornposition, equipment, preferred properties, etc.

The mixingis not restricted to a set procedure. One acceptable procedure is to mix the ingredients together atrelatively low temperatures. (20-100" C.) and then pour the mixture into a mold at the desired curing temperature. Ifthe polyepoxide composition is a solid, then it must be melted prior to its being mixed with the dianhydride.

No elaborate equipment is necessary for the performance of the present invention, and thus standard equipment for the curing of resinous composition can be used. While it is generally undesirable and unnecessary to use other materials, they may be added to the polyepoxy composition-dianhydride reaction mixture.

The following examples illustrate the performance of the present invention, butfthe present invention is not expressly limited thereto. l 7

Example 1 Epon 828 1 (25 grams) was placed in a glass reaction vessel equipped with thermometer, stirrer and heating mantle and was heated to C. 1,2,3,4-cyclopentanetetracarboxylic dian'hydride (7.2 grams) was added thereto and the mixture stirred for about 15 minutes. The cleared solution was then poured into a test tube where it gelled. t

1 Epon 828 is the trade name of Shell Chemical Corp. for a liquid epoxy resin having an epoxide equivalent of 1 mol per 200 grams of resin prepared -by the condensation reaction of 2,2-bis(4,4"hydroxyphenyUpropane and epichlorohydrin.

Thus, from about 0.1 to 0.5 mol of 1,2,3,4-

'hydrin.

7 Example 2 Epon.828 (25 grams) was placed in a glass reaction" J'vesselequipped with thermometer, stirrer and heating v mantleand-was heated to 165 C. 1,2,3,4-cyclopentanetetracarboxylicdianhydride (7.2 grams) which had been mechanically ground was added thereto and the mixture stirredfor about minutes. Then'the reaction mixture was poured into a. preheated tube and placed in an oven at 200 for aboutfl16 hours. At that time the material had bodied and was found to be a hard, tough product. v

. Exantplefjh I npsn 828 ('25 grams) was placed in a glass reaction [vessel equipped with thermometer, stirrer and heating mantle and wasiheated to 165 C. Powdered 1,2,3,4-

added thereto and themixture' stirred for about 15 minutes. Then" the reaction mixture was poured into' a preheated tube and placedin an oven at 200 C. for about 64 hours. After removalfrom the oven the product was foundto be ahard, tough casting.

Example 4 Epon 828 ("grams) was" placed in a beaker with a, constant temperaturebath maintainedat' 150 C.

Powdered f1,2,3,4-cyclopentanetetracarboxylic dianhydride 11.1" grams) was'added thereto and the reaction I mixture stirred for about F10 minutes. Then the beaker :was removed from the bath and placed in an oven at 200 C. temperaturefor about 16 hours. At that time the cured product was extremely hard as evidenced by the I inability to dent with 'a file even at 200 C.

I Example 5 In order to determine the potlife of the reaction mix- I titre, Epon 828 (25 grams) was placed in a beaker coni tained in a constant temperature bath at 160 C. Powdered "i (7.2 grams) was added thereto and the mixture stirred for 1,2,3,4 cyclopentanetetracarboxylic' dianhydride about 18 minutes at which time it gelled. I

i I I I Examplefi Epon 1001 2 (62.5 grams) is placedin a glass reaction mantle and is heated to about 160 C. 1,2,3,4-cyclopentanetetracarboxylic dianhydride (7.2. grams) is added thereto and the mixturestirredforabOut 15 minutes. Then the reaction mixture is poured into a preheated tube and placed in an oven at 180 C. for about 16 hours. At that time the product is determined to be a hard, tough casting. 1

'Example 7 'cyclopentanetetracarboxylic dianhydride (11.1 g.) was I i irane oxygen atom and 1,2, 3,4-cyclopentanetetraoarboxfor 20 hours. 'At that time the product is determined to be a hard, tough casting. I

Example 9 Epoxide 201 3 (17 grams) is placed in a glass reaction vessel equipped with thermometer, stirrer and heating mantle and is heated to about 160 C. 1,2,3,4-cyclopentanetetracarboxylic dianihydride (7.2 grams) is added thereto and the mixture stirred for about fifteen minutes. Then the reaction mixture is poured into a preheated tube and placed in an oven at 200 C. for-24 hours. At that time the product is determined to be a hard, tough I 1. A composition of matter 'comprising the reaction,

product of a polyepoxide containing more than one oxylic dianhy-dride, the dianhydri'de reactant being presen in the dianhydride form.

2. A composition of matter comprising the reaction product of a diepoxide containing two oxirane oxygen atoms and"1,2,3,4-cyclopentanetetracarboxylic dianhy-,

dride, the dianhydride reactant being present in the dianhydride form. I I

3. A "composition of matter comprising the reaction productof 1) the reaction product containing more than one oxir ane oxygen atom of an epih-alogenhydrin and abis-phenol and (2) 1,2,3,4-cyclopentanetetracarboxylic diarrhydride, the dianhydride reactant being present in the dianhydride form. I

' 4. A composition of matter comprising'the reaction product of a polyepoxy compound containing more than one oxirane oxygen atom and from about 0.1 to about i vessel equipped with thermometer, stirrer and heating 1;*2,5,6 dicyclopentane diepoxide (9.0 grams) is placed 'in' a glass reaction vesselequipped with thermometer,

stirrer and heatingmantle' and is heated toabout 160 C, Powdered 1,2,3,4-cyclopentanetetracarboxylic dianhydride (7.2 grams) is added thereto and the mixture stirred for about .15 minutes. Then the reaction mixture is poured intoa' preheated tube and placed in anovenat 220 C. for

0.5 mol of 1,2,3,4-cyclopentanetetraoarboxylic dianhydride per epoxide equivalent of the polyepoxide com pound, the dianhydride reactant being present in the di- 'anhydride form.

5. A composition of matter comprisingthe reaction product of a diepoxy compound containing two ox-irane oxygen atoms (and from about 0.1 to about 0.5 mol' of 1,2,3,4-cyclopentanetetraoarboxylic dianhydride per epox ide equivalent of the diepoxide compound, the dian'hydride reactant being present in the dianhydride form.

6. A composition of matter comprising the reaction product of (l) the reaction product containing more than one oxirane oxygen atomof an epihalogenhydrin I and 2,2-bis(4,4-hydroxyphenyl)propane and (2) from 12 hours, At that time the product is determined to be a hard, tough casting. .1

I I I Example 8 I I iBis-cyclopentanyl ether diepoxide (11.5 grams) is placed in a glass reaction vessel equipped with thermometer,

stirrer and heating mantle and is heated toabout 160 v1,2,3;4-cyclopentanetetracarboxylic dianhydri de (7.2 grams) is gadd'ed thereto and the mixture stirred for about fifteen minutes. Then the reaction mixture is, poured 1 into a preheatedltube and placed in an oven at 200 C.

*Ep'on 100.1 is the trade name of ShellChemical Corp. for. a solid epoxy resin having an epoxide equivalent of l n10] pen450-525 grams'ofresin, prepared by the condensation reaction of 2,2-bis(4,4-hydr0xyphenyl)propane and epichloroabout 0.2 to about 0.3 mol of 1,2,3,4-cyclopentanetetracarboxylic dianhydride per epoxide equivalent ofthe diepoxide compound, the dianhydnide reactant being present in the =dianhydride' form.

' 7. A composition of matter comprising the reaction product of (1) the reaction product containing more than one oxirane oxygen atom of epichlorohydrin and 2,2-bis (4,4-hydroxypheny1)propane and (2) about 0.25 rnol of 1,2,3,4=cyclopentanetetracarboxylic dian'hydride per epoxide equivalent of (1), the 'dian'hydride reactant being presentin'thedianhydride form. I

.8. A composition of matter comprising the reaction product of bis-cyclopentylether diepoxide'and about 0.4 to about 0.6 mol of 1,2,3,4-cyclopentanetetnacarboxylic dianhydride per mol of bis-'cyclopentyl ether diepoxide,

Epoxide 201 is the trade name of UDiOIL'CZIIbidO Chemicals Company for 3;4epoxy-6-methylcyclohexyhnethy1-3,4- epoxy-6-methylcyclohexanecarboxylate. Y

the dianhydride reactant being present in the dianhydride form.

9. A composition of matter comprising the reaction product of dicyclopentadiene diepoxide and about 0.4 to about 0.6 moi of 1,2,3,4 cyclopentanetetracarboxylic dianhydride per mol of dicyolopentadiene diepoxide, the dianhydride reactant :being present in the dianhydride form.

10. A composition of matter comprising the reaction product of 3,4 epoxy 6 methylcyclohexylmethyl 3,4- epoxy-6-methylcyolohexanecarboxylate and from about 0.4 to about 0.6 mol of 1,2,3,4-cyclopentanetetracarboxylic di anhydride per mol of the epoxy compound, the dianhydride reactant 'being present in the :di'anhydride form.

11. A method for the curing of a polyepoxide containing more than one oxirane oxygen atom which comprises heat-reacting it with 1,2,3,4-cyclopentanetetracarboxylic dianhydride, the dianhydride reactant 'being present in the dianhydnide form. t

12. Method of claim 11 wherein 1,2,3,4-cyclopentane dianhydride is present in quantities of from: about 0.4 to about 0.6 mol per epoxide equivalent of the polyepoxide compounds based on its oxirane atoms.

13. Method of claim 11 wherein the polyepoxide compound contaim'ng more than one oxirane oxygen atom 6 is the reaction product of epiehlorohydrin and 2,2-'lais(4, 4'hydroxypheny1)propane.

14. Method of claim 11 wherein the polyepoxide compound is bis-'cyolopenty-l ether diepoxide.

15. Method ofol-airn 11 wherein the polyepoxide compound is dicyclopentadiene diepoxide.

16. Method of claim 11 wherein the polye'poxide compound is 3,4-epoxy-6-methylcyelohexyhnethyl-3,4-epoxy- 6-methylcyelohexanecarboxylate.

17. Method of claim 11 wherein the dianhydride is the sole curing agent.

References Cited in the file of this patent UNITED STATES PATENTS 2,324,483 Castan July 20, 1943 2,768,153 Shokal Oct. 23, 1956 2,965,610 Newey Dec. 20, 1960 OTHER REFERENCES Charlton: Modern Plastics, v01. 32, No. 1, pages 155- 161 and 240-243 (September 1954).

Weiss: Industrial and Engineering Chemistry, vol. 49, pages 1089-1090 (July 1957).

Lee et 21.: Epoxy Resins, McGraw-Hi-ll Book 00., Inc., N.Y., 1957, pages -131 relied on. 

1. A COMPOSITION OF MATTER COMPRISING THE REACTION PRODUCT OF A POLYEPOXIDE CONTAINING MORE THAN ONE OXIRANE OXYGEN ATOM AND 1,2,3,4-CYCLOPENTANETETRACARBOXYLIC DIANHYDRIDE, THE DIANHYDRIDE REACTANT BEING PRESENT IN THE DIANHYDRIDE FROM. 